The invention relates to a personnel access-control device in the form of a turnstile for controlling access to a defined area.
Personnel access-control devices are well known in the prior art. For example, a device is known from EP 1 023 698 B1 in which an antenna unit for communication with an RFID (radio-frequency identification device) transponder acts as data medium in which access authorization is stored. Personnel access-control devices further include a blocking device actuated via a control circuit by an actuator in order to allow a person to enter or exit a building or controlled space. For this, the blocking device is released from a blocking position into a free position upon readout of a valid access authorization. In the free position, access is provided to a person, and/or the width of a passage is not restricted. In contrast, access is denied in the blocking position. In such access-control devices, a turnstile is often used as the blocking device.
Turnstiles as known in the art include a main shaft directed downward that is mounted on a carrier, and to which, for example, three blocking arms are affixed. Alternatively, the main shaft may include one or two blocking arms. The pivot axis of the main shaft is advantageously inclined at 30° to 60° to the horizontal, particularly at 45°, whereby the angle of the blocking arms to the pivot axis is 30° to 60°, and advantageously 45°. In a projection to the plane perpendicular to the pivot axis, the angle between the blocking arms for three blocking arms is 120°, and 180° for two blocking arms. Tilting of the pivot axis reduces the direct angle between blocking arms (˜83° with 3 blocking arms, ˜80° with 2 blocking arms).
Furthermore, the carrier to which the main shaft is mounted may be implemented as a post to which is secured a reader device that, upon read-out of a valid access authorization, triggers an actuator to rotate the main shaft and thus to provide access.
In the case of access-control devices for personnel that read access authorizations from RFID transponders without contact, the reader device includes a housing with an antenna unit oriented along the passage direction and advantageously extending from above to below in order to be able to read the RFID transponder. For this, a suitable electronic circuit to control the antenna unit may also be mounted within this housing.
The laterally-positioned RFID antenna units known in the art are disadvantageously expensive and require substantial installation space. Furthermore, concentrating the electromagnetic or magnetic field based on the volume of passing persons, and thus reducing signal cross-talk to and from adjacent access points, is linked to considerable expense. Screening measures required to accomplish this cause a significant redaction in the identification range, and must be carefully compensated using suitable electronic means.
Disadvantageously, using known personnel control devices that use laterally-mounted RFID antenna units may detect persons in adjacent access points, or may detect several persons standing in line from electromagnetic or magnetic fields of the antenna units, which detracts from the function of access-control devices and from user convenience.